Evaluation of the Effect of Pear Stone Cells on the Recovery of Multi-Class Pesticides

Abstract

The widespread sample preparation method for the extraction of pesticide residues, the QuEChERS method, sometimes yields different pesticide recovery values for different food matrices. Pear (Pyrus communis L.) is an example of a matrix that can be characterized with somewhat lower pesticide recoveries. In order to investigate the reason for this result, the most characteristic structural feature of pears, the stone cells, possessing a specific surface due to their greater cellulose and lignin contents, were isolated and purified. The isolated stone cells were used for the preparation of a model sample in combination with tomato, a food matrix showing high pesticide recovery values, in a pesticide spiking experiment. Eleven multi-class pesticides were selected for the study where the quantification was carried out with HPLC-ESI-MS/MS. No significant differences were found between the pesticide recoveries obtained from the tomato and the combined tomato-pear stone cells matrices, which indicates the reason behind the lower pesticide recoveries in pear matrices is still to be determined.

Keywords:

• LC-MS/MS
• Pear
• Pesticide
• QuEChERS
• Sclereid cell
• Stone cell

Acknowledgments

This paper is part of a special issue organized by Dr. Nikolaos Thomaidis and Dr. Antony C. Calokerinos from research presented at the Aegean Analytical Chemistry Days Conference in Lesvos, Greece on 29 September–3 October 2010.

The financial support of TÁMOP 4.2.1/B-09/1/KMR-2010-0005 is gratefully acknowledged. The authors would also like to thank the technical help of Mihály Dernovics.

Notes

MW, molecular weight; DP, declustering potential; EP, entrance potential; CEP, collision cell entrance potential; CE, collision energy; CXP, collision cell exit potential.